Certain known wind power turbines feed energy to the electric power grid at a designated or given voltage, which must be the same as that of the grid, and supplies a designated or given current. The grid voltage is established by the electric power server to which the wind power turbine is connected, whereas the current output depends on the wind available and the power demand by the server.
During operation of such wind power turbines, malfunctions may occur (e.g., involving wind power turbine component parts or the electric power grid).
A malfunction in the electric transmission system produces a so-called torque breach (i.e., a sudden variation in torque on the shaft).
This torque breach produces severe stress and oscillation on the rotor, and particularly the blades, which may result in breakage of the blades.
To prevent this, the rotor and blades must be designed to withstand severe stress and oscillation, which includes equipping the wind power turbine with rotary structures, in particular blades, that are reinforced and oversized with respect to ordinary loads, thus increasing the weight and cost of the wind power turbine.